Why syntax is “driver.manage().window().maximize();”?

In my last post, I explained about some useful methods of WebDriver. I got some comments to explain why do we write syntax as below:

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driver.manage().window().maximize();// To maxmize

driver.navigate().to("some url");// To open url

driver.manage().timeouts().implicitlyWait(30,TimeUnit.SECONDS);// To set implicit time

Actually it’s JAVA concept. It is called as method chaining. We will learn about this now.

Some basic Concepts of JAVA:
1. There can be two types of members in a java class. Static and Non-static.
2. Static methods can be called using class name or by creating an object of that class but calling by class name is perfect practice.
3. Non-static members of class can be called only through object of class.
4. A method can return a type. It may be class or interface as well.

Explanation:
1. There are total three classes “Demo”, “AnotherDemo” and “NewDemo”.
2. Class “Demo” has a method “DemoMethod” which return an object of class “AnotherDemo”.
3. Class “AnotherDemo” has a method “AnotherDemoMethod” which return an object of class “NewDemo”.
4. Class “NewDemo” has a method “NewDemoMethod” which return void.
5. Only class “Demo” has main method and through that method we want to access “NewDemoMethod” of class “NewDemo”.
6. We created an object of “Demo” to access method present in class “Demo”.

Demo DemoObject= new Demo();
7. Now, we will call “DemoMethod” of class “Demo” which returns an object of class “AnotherDemo”, which we can store in a variable of type “AnotherDemo”.

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AnotherDemo AnotherDemoObject=DemoObject.DemoMethod();

8. Now what we have?? An object of class “AnotherDemo” means we can access methods of class “AnotherDemo”.
9. We call method “AnotherDemoMethod1” of class “AnotherDemo” which returns an object of class “NewDemo”, which we can store in a variable of type “NewDemo”.
NewDemo NewDemoObject= AnotherDemoObject.AnotherDemoMethod();

10. Now, we can access method of “NewDemo”.
NewDemoObject.NewDemoMethod();

11. So, now we have following lines of code:

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Demo DemoObject=newDemo();

AnotherDemo AnotherDemoObject=DemoObject.DemoMethod();

NewDemo NewDemoObject=AnotherDemoObject.AnotherDemoMethod();

NewDemoObject.NewDemoMethod();

12. Now, refer the below image:
13. Above code has concepts of method chaining and anonymous object. When we need to use object once in a program, we can go for anonymous object for better memory utilization.

I hope above java concept must be clear.
Same logic is applied for selenium. I will explain one statement:
driver.manage().window().maximize();

When we call manage() method, it returns a “Options” type. “Options” is an interface.

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publicOptions manage()

{

returnnewRemoteWebDriver.RemoteWebDriverOptions();

}

Interface “Options” has method “windows” which returns “Window” type.

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publicinterfaceOptions{

WebDriver.Window window();

}

Now, we can use any method of interface “Window”. it has following methods which can be called.

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publicinterfaceWindow{

voidsetSize(Dimension arg0);

voidsetPosition(Point arg0);

Dimension getSize();

Point getPosition();

voidmaximize();

voidfullscreen();

}

See complete code below:

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WebDriver driver=newChromeDriver();

Options optnObj=driver.manage();

Window winObj=optnObj.window();

winObj.maximize();

// We can write above lines of code in one line as

driver.manage().window().maximize();

That’s it. I hope you must have learnt new thing. If still you have doubt,feel free to comment or do email.
I strongly believe when you know answer of both “how” and “Why”, you can write better scripts.

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Very nice Amod. But I dare asking you one silly question to your standard.

With your nice explanation I reach to maximize() method but how selenium understands that it has to maximize the window and by what dimensions? I mean to say where do we have a code which say to Selenium to maximize the window by this rate??? Because Interface Window has got maximize() method but it does not have an implementation(for the right reason as it is an interface).

It’s a great explanation. Thanks for explaining this topic. But I have one doubt here in which class the option & Windows interface are implemented how the instance creation is happen for option & Windows methods.